The thesis analyses the 2013 Cohesion Policy reform as a case of European integration. By revisiting neofunctionalism and combining it with the Multiple Streams approach, it is possible to provide a new angle to the phenomenon of the Cohesion Policy’s integration into the European economic governance framework. The thesis utilises qualitative content analysis to systematically analyse the dynamics that influenced the reform process and eventually lead to the establishment of new integrative linkages. It is revealed how the integration dynamics originated in the economic policy arena and spilled over into the Cohesion Policy reform. Consequently, the thesis concludes that the neofunctionalist concept of functional spillover remains a powerful analytical tool and it is shown in what way neofunctional mechanisms continue to materialise in the European polity.